Changes from Version 0.04:
All modes of operation recommended by NIST as of July 2001 (ECB, CBC, CFB-128,
OFB, and CTR) are implemented, with the exception of n-bit CFB mode. I can't
think of a way to do it without adding yet another incompatible method...
An incompatible (to Crypt::CBC) method of changing the IV's for the
modes which require it has been added.